JP2015217445A - Polishing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing device capable of applying intended local load from a local load application device to a retainer ring even when the local load application device and the retainer ring are relatively inclined.SOLUTION: A polishing device includes: a retainer ring 20 pressing against a polishing surface while rotating together with a head body 10; a stationary ring 91 disposed on an upper side of the retainer ring 20; and a local load application device 30 for applying local load to a part of the retainer ring 20 via the stationary ring 91. The local load application device 30 includes a load transmission section connected to the stationary ring 91. The load transmission section includes a mechanism 110 for allowing a relative inclination between the local load application device 30 and the retainer ring 20.

Description

  The present invention relates to a polishing apparatus for polishing a substrate such as a wafer, and more particularly to a polishing apparatus provided with a retainer ring surrounding the periphery of the substrate.

  In recent years, with higher integration and higher density of semiconductor devices, circuit wiring has become increasingly finer and the number of layers of multilayer wiring has increased. When trying to realize multilayer wiring while miniaturizing the circuit, the step becomes larger while following the surface unevenness of the lower layer, so as the number of wiring layers increases, the film coverage to the step shape in thin film formation (Step coverage) deteriorates. Therefore, in order to carry out multilayer wiring, it is necessary to improve the step coverage and perform a flattening process in an appropriate process. Further, since the depth of focus becomes shallower as the optical lithography becomes finer, it is necessary to planarize the surface of the semiconductor device so that the uneven steps on the surface of the semiconductor device are kept below the depth of focus.

Therefore, in the semiconductor device manufacturing process, planarization of the surface of the semiconductor device has become increasingly important. The most important technique for planarizing the surface is chemical mechanical polishing (CMP). In this chemical mechanical polishing, polishing is performed by bringing a wafer into sliding contact with the polishing surface while supplying a polishing liquid containing abrasive grains such as silica (SiO ₂ ) onto the polishing surface of the polishing pad.

  FIG. 13 is a schematic diagram showing a polishing apparatus for performing CMP. The polishing apparatus includes a polishing table 203 that supports the polishing pad 202, a polishing head 201 for holding the wafer W, and a polishing liquid supply nozzle 205 that supplies a polishing liquid (slurry) onto the polishing pad 202. . The polishing pad 202 is rotated together with the polishing table 203, and the polishing liquid is supplied onto the rotating polishing pad 202. The polishing head 201 presses the wafer W against the polishing surface 202a of the polishing pad 202 with a predetermined pressure while holding the wafer W. The surface of the wafer W is polished by a mechanical action by abrasive grains contained in the polishing liquid and a chemical action by chemical components contained in the polishing liquid.

  When the relative pressing force between the wafer W being polished and the polishing surface 202a of the polishing pad 202 is not uniform over the entire surface of the wafer W, polishing is performed according to the pressing force applied to each part of the wafer W. Insufficient or excessive polishing occurs. Therefore, in order to equalize the pressing force on the wafer W, a pressure chamber formed of an elastic film is provided below the polishing head 201, and a fluid such as air is supplied to the pressure chamber so that the fluid flows through the elastic film. The wafer W is pressed by pressure.

  Since the polishing pad 202 has elasticity, the pressing force applied to the edge portion (peripheral portion) of the wafer W being polished becomes non-uniform, so that only the edge portion of the wafer W is polished. It may happen. In order to prevent such edge fringing, a retainer ring 220 that holds the edge portion of the wafer W is provided so as to be movable up and down with respect to the head body, and the polishing surface 202a of the polishing pad 202 positioned on the outer peripheral edge side of the wafer W is retained by the retainer. The ring 220 is pressed.

  Since the retainer ring 220 presses the polishing pad 202 around the wafer W, the load of the retainer ring 220 affects the profile of the edge portion of the wafer W. In order to positively control the profile of the edge portion of the wafer W, a local load may be applied to a part of the retainer ring 220. Therefore, the polishing apparatus shown in FIG. 13 includes a local load applying device 230 that applies a local load to a part of the retainer ring 220. The local load applying device 230 is fixed to the head arm 216.

  FIG. 14 is a perspective view showing the local load applying device 230 and the polishing head 201. As shown in FIG. 14, a stationary ring 235 is disposed on the retainer ring 220. The local load applying device 230 includes a pressing rod 231 that transmits a downward local load to the retainer ring 220, and a lower end of the pressing rod 231 is fixed to the stationary ring 235. While the wafer W is being polished, the retainer ring 220 rotates, but the stationary ring 235 and the local load applying device 230 do not rotate. The stationary ring 235 includes a roller (not shown), and this roller is in rolling contact with the upper surface of the retainer ring 220. The local load applying device 230 transmits a downward local load from the pressing rod 231 to the retainer ring 220 via the stationary ring 235.

  The rotating retainer ring 220 may be inclined due to processing accuracy or surface irregularities of the polishing pad 202. Since the pressing rod 231 is fixed to the stationary ring 235, when the retainer ring 220 is inclined, the pressing rod 231 is also inclined. When the pressing rod 231 is tilted, an excessive frictional resistance is generated in a linear guide (not shown) that supports the pressing rod 231, and an intended local load may not be applied to the retainer ring 220. In such a case, a desired polishing result cannot be obtained, which causes a variation in film thickness particularly at the peripheral edge of the wafer W.

  Further, when the local load applying device 230 is assembled to the head arm 216, the local load applying device 230 may be slightly inclined with respect to the retainer ring 220. When the local load applying device 230 is inclined with respect to the retainer ring 220, stress is applied to the pressing rod 231 in a direction other than the vertical direction, and excessive frictional resistance is generated in the above-described linear guide (not shown). End up. Also in this case, a desired polishing result cannot be obtained, and this causes a variation in film thickness particularly at the peripheral edge of the wafer W.

  Furthermore, when the polishing table 203 is rotating, the surface of the polishing table 203 may also fluctuate up and down. This vertical fluctuation of the polishing table 203 causes the entire retainer ring 220 to vibrate up and down. Since the local load applying device 230 has large inertia and frictional resistance, it cannot absorb this vibration, and the local load on the retainer ring 220 varies.

JP 2014-4675 A

  Therefore, an object of the present invention is to provide a polishing apparatus capable of applying an intended local load from the local load applying device to the retainer ring even when the local load applying device and the retainer ring are relatively inclined. .

  One aspect of the present invention includes a head main body that is pressed against a polishing surface while rotating the substrate, a retainer ring that is disposed so as to surround the substrate and presses the polishing surface while rotating together with the head main body, and an upper portion of the retainer ring. And a local load applying device that applies a local load to a part of the retainer ring through the stationary ring, and the local load applying device is connected to the stationary ring. And the load transmitting portion includes a mechanism that allows a relative inclination between the local load applying device and the retainer ring.

In a preferred aspect of the present invention, the mechanism is a tilting universal joint.
In a preferred aspect of the present invention, the tiltable universal joint can be tilted only in a tangential direction of the retainer ring at a location where the load transmitting portion is connected to the stationary ring.
In a preferred aspect of the present invention, the load transmission unit includes a pressing member connected to the stationary ring and the tilting universal joint fixed to the pressing member.

In a preferred aspect of the present invention, the tiltable universal joint can be tilted in multiple directions.
In a preferred aspect of the present invention, the load transmitting portion includes two pressing rods for transmitting the local load and two spherical bearings that support the two pressing rods so as to be tiltable, and are capable of tilting. The joint is composed of the two spherical bearings.
In a preferred aspect of the present invention, the two spherical bearings include two bearing housings and two protrusions that make point contact with the two bearing housings, respectively.

In a preferred aspect of the present invention, the load transmission unit further includes a vibration absorbing member.
In a preferred aspect of the present invention, the vibration absorbing member is a spring.
In a preferred aspect of the present invention, the vibration absorbing member is rubber.

  Even when the local load applying device and the retainer ring are relatively inclined due to surface irregularities of the polishing pad, this inclination is absorbed. Therefore, unnecessary force does not occur in the local load applying device and the retainer ring, and the local load applying device can transmit the target local load to the retainer ring.

It is a mimetic diagram showing the polish device in one embodiment of the present invention. It is a perspective view which shows a local load provision apparatus. It is sectional drawing of a grinding | polishing head. It is a side view which shows a press rod, a stationary ring, and a roller. It is an enlarged view of the spherical bearing shown in FIG. It is a figure which shows other embodiment of a tilting universal joint. It is a figure which shows the state which the tilting universal joint inclined. It is a perspective view which shows the local load provision apparatus and polishing head in which the tilting universal joint shown in FIG. 6 was integrated. It is a figure which shows other embodiment of a load transmission part. It is a figure which shows other embodiment of a load transmission part. It is a figure which shows other embodiment of a load transmission part. It is a figure which shows other embodiment of a load transmission part. It is a schematic diagram which shows the grinding | polishing apparatus for performing CMP. It is a perspective view which shows the conventional local load provision apparatus and a grinding | polishing head.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding components are denoted by the same reference numerals, and redundant description is omitted.
FIG. 1 is a schematic diagram showing a polishing apparatus according to an embodiment of the present invention. As shown in FIG. 1, the polishing apparatus includes a polishing head (substrate holding apparatus) 1 that holds and rotates a wafer that is an example of a substrate, a polishing table 3 that supports a polishing pad 2, and a polishing liquid ( And a polishing liquid supply nozzle 5 for supplying a slurry. The upper surface of the polishing pad 2 constitutes a polishing surface 2a for polishing the wafer.

  The polishing head 1 is connected to the lower end of the polishing head shaft 11. The polishing head shaft 11 is rotatably held by a head arm 16. A rotating device (not shown) for rotating the polishing head shaft 11 and a lifting device (not shown) for raising and lowering the polishing head shaft 11 are arranged in the head arm 16. The polishing head 1 is rotated via a polishing head shaft 11 by a rotating device, and the polishing head 1 is raised and lowered via the polishing head shaft 11 by an elevating mechanism. The head arm 16 is fixed to the turning shaft 15, and the polishing head 1 can be moved to the outside of the polishing table 3 by the rotation of the turning shaft 15.

  The polishing head 1 is configured to hold the wafer on the lower surface thereof by vacuum suction. The polishing head 1 and the polishing table 3 rotate in the same direction as indicated by arrows, and in this state, the polishing head 1 presses the wafer against the polishing surface 2 a of the polishing pad 2. A polishing liquid is supplied onto the polishing pad 2 from the polishing liquid supply nozzle 5, and the wafer is polished by sliding contact with the polishing pad 2 in the presence of the polishing liquid.

  The polishing head 1 includes a head main body 10 that presses the wafer against the polishing pad 2 and a retainer ring 20 that is disposed so as to surround the wafer. The head body 10 and the retainer ring 20 are configured to rotate integrally with the polishing head shaft 11. The retainer ring 20 is configured to be movable up and down independently of the head body 10. The retainer ring 20 projects outward from the head body 10 in the radial direction. A local load applying device 30 that applies a local load to a part of the retainer ring 20 is disposed above the retainer ring 20.

  The local load applying device 30 is fixed to the head arm 16. The retainer ring 20 during polishing rotates around its axis, but the local load applying device 30 does not rotate integrally with the retainer ring 20, and its position is fixed. A stationary ring 91 is disposed above the retainer ring 20. A plurality of rollers 53 are arranged between the retainer ring 20 and the stationary ring 91. The stationary ring 91 is connected to the local load applying device 30.

  The stationary ring 91 does not rotate and its position is fixed. The plurality of rollers 53 are held by a stationary ring 91, and the rollers 53 are in rolling contact with the rotating retainer ring 20. The local load applying device 30 applies a downward local load to a part of the retainer ring 20 via the stationary ring 91 and the roller 53. The downward local load is transmitted to the retainer ring 20 through the stationary ring 91 and the roller 53, and the retainer ring 20 presses the polishing surface 2 a of the polishing pad 2. The reason why a downward local load is applied to a part of the retainer ring 20 during polishing of the wafer is to positively control the peripheral edge (edge) profile of the wafer.

  FIG. 2 is a perspective view showing the local load applying device 30. As shown in FIG. 2, the local load applying device 30 includes two pressing rods 31, a bridge 32, a plurality of air cylinders (load generating devices) 33, 34, 35, a plurality of linear guides 38, a plurality of guide rods 39, The unit base 40 is mainly configured.

  The unit base 40 is fixed to the head arm 16. A plurality of (three in the illustrated example) air cylinders 33, 34, 35 and a plurality of (four in the illustrated example) linear guides 38 are attached to the unit base 40. The piston rods of the air cylinders 33, 34, and 35 and the plurality of guide rods 39 are connected to a common bridge 32. The plurality of guide rods 39 are supported by a linear guide 38 so as to be movable up and down with low friction. By these linear guides 38, the bridge 32 can be moved up and down smoothly without tilting.

  The air cylinders 33, 34, and 35 are respectively connected to an independent pressure adjusting device (not shown) and an atmosphere release mechanism (not shown), and are configured to be able to generate loads independently of each other. Loads generated by the air cylinders 33, 34, and 35 are transmitted to the common bridge 32. The bridge 32 is connected to the stationary ring 91 by a pressing rod (pressing member) 31, and the pressing rod 31 transmits the load of the air cylinders 33, 34, and 35 applied to the bridge 32 to the stationary ring 91. The reason why there are three air cylinders is that the local load is located below the head arm 16 and the air cylinder cannot be placed directly above it. This is to match the position of the load. In the present embodiment, there are three cylinders. However, by strengthening the linear guide mechanism, only one cylinder may be provided, or a cylinder may be disposed under the head arm 16.

  The polishing head 1 rotates about its own axis, but the local load applying device 30 is fixed to the head arm 16 and therefore does not rotate with the polishing head 1. That is, during polishing of the wafer, the polishing head 1 and the wafer are rotating, while the local load applying device 30 is stationary at a predetermined position. Similarly, the stationary ring 91 is stationary at a predetermined position during polishing of the wafer.

  Next, the polishing head 1 as a substrate holding device will be described. FIG. 3 is a cross-sectional view of the polishing head 1. The polishing head 1 includes a head body 10 and a retainer ring 20. The head main body 10 includes a carrier 43 connected to the polishing head shaft 11 (see FIG. 1), an elastic film (membrane) 45 attached to the lower surface of the carrier 43, and a retainer ring disposed so as to surround the elastic film 45. 20 and a spherical bearing 47 that supports the retainer ring 20 while allowing the retainer ring 20 to tilt and move up and down with respect to the carrier 43. The retainer ring 20 is connected to and supported by the spherical bearing 47 via a connecting member 75. The connecting member 75 is disposed in the carrier 43 so as to be movable up and down.

  The lower surface of the elastic film 45 constitutes a circular substrate contact surface, and this substrate contact surface is in contact with the upper surface of the wafer W (the surface opposite to the surface to be polished). A plurality of through holes (not shown) are formed in the substrate contact surface of the elastic film 45. A pressure chamber 46 is formed between the carrier 43 and the elastic film 45. The pressure chamber 46 is connected to a pressure adjusting device (not shown). When pressurized fluid (for example, pressurized air) is supplied to the pressure chamber 46, the elastic film 45 that receives the fluid pressure in the pressure chamber 46 presses the wafer W against the polishing surface 2 a of the polishing pad 2. When a negative pressure is formed in the pressure chamber 46, the wafer W is held on the lower surface of the elastic film 45 by vacuum suction.

  The retainer ring 20 is disposed so as to surround the wafer W and the elastic film 45. The retainer ring 20 includes a ring member 20a that comes into contact with the polishing pad 2, and a drive ring 20b fixed to the upper portion of the ring member 20a. The ring member 20a is coupled to the drive ring 20b by a plurality of bolts (not shown). The ring member 20a is disposed so as to surround the outer peripheral edge of the wafer W.

  The connecting member 75 includes a shaft portion 76 disposed in the center portion of the head body 10 and a plurality of spokes 78 extending radially from the shaft portion 76. The shaft portion 76 extends in the vertical direction within the spherical bearing 47 disposed at the center of the head body 10. The shaft portion 76 is supported by the spherical bearing 47 so as to be movable in the vertical direction. The drive ring 20b is connected to the spoke 78. With such a configuration, the connecting member 75 and the retainer ring 20 connected thereto can be moved in the vertical direction with respect to the head body 10.

  The spherical bearing 47 includes an inner ring 48 and an outer ring 49 that slidably supports the outer peripheral surface of the inner ring 48. The inner ring 48 is connected to the retainer ring 20 via a connecting member 75. The outer ring 49 is fixed to the carrier 43. The shaft portion 76 of the connecting member 75 is supported by the inner ring 48 so as to be movable up and down. The retainer ring 20 is supported by a spherical bearing 47 via a connecting member 75 so as to be tiltable.

  The spherical bearing 47 allows the retainer ring 20 to move up and down and tilt, while restricting lateral movement (horizontal movement) of the retainer ring 20. During polishing of the wafer W, the retainer ring 20 receives a lateral force (a force directed outward in the radial direction of the wafer W) from the wafer W due to friction between the wafer W and the polishing pad 2. This lateral force is received by the spherical bearing 47. As described above, the spherical bearing 47 is subjected to the lateral force that the retainer ring 20 receives from the wafer W due to the friction between the wafer W and the polishing pad 2 during the polishing of the wafer W (toward the radial outside of the wafer W). The retainer ring 20 functions as a support mechanism that restricts the lateral movement of the retainer ring 20 (that is, fixes the horizontal position of the retainer ring 20).

  A plurality of pairs of driving collars 80 are fixed to the carrier 43. Each pair of drive collars 80 is disposed on both sides of each spoke 78, and the rotation of the carrier 43 is transmitted to the retainer ring 20 via the drive collar 80, whereby the head body 10 and the retainer ring 20 are integrated. Rotate. The drive collar 80 is only in contact with the spoke 78 and does not prevent the connecting member 75 and the retainer ring 20 from moving up and down and tilting.

  The upper part of the retainer ring 20 is connected to an annular retainer ring pressing mechanism 60. The retainer ring pressing mechanism 60 applies a uniform downward load to the entire upper surface of the retainer ring 20 (more specifically, the upper surface of the drive ring 20b), and the lower surface of the retainer ring 20 (that is, the lower surface of the ring member 20a). ) Is pressed against the polishing surface 2 a of the polishing pad 2.

  The retainer ring pressing mechanism 60 includes an annular piston 61 fixed to the upper part of the drive ring 20 b and an annular rolling diaphragm 62 connected to the upper surface of the piston 61. A pressure chamber 63 is formed inside the rolling diaphragm 62. The pressure chamber 63 is connected to a pressure adjusting device (not shown). When pressurized fluid (for example, pressurized air) is supplied to the pressure chamber 63, the rolling diaphragm 62 pushes down the piston 61 downward, and the piston 61 pushes down the entire retainer ring 20 downward. In this way, the retainer ring pressing mechanism 60 presses the lower surface of the retainer ring 20 against the polishing surface 2 a of the polishing pad 2.

  The lower end of the pressing rod 31 of the local load applying device 30 is connected to the stationary ring 91. The local load applying device 30 applies a downward local load to the stationary ring 91 through the pressing rod 31. Further, the downward local load is transmitted to the retainer ring 20 through the roller 53.

  There are several reasons for using two pressing rods 31. The first reason is to prevent the pressing rod 31 from being inclined and becoming unstable. The second reason is to prevent the stationary ring 91 from rotating around the pressing rod 31. The third reason is that the load point of the two pressing rods 31 is located at the intermediate point between the two pressing rods 31, so that the load point is positioned on the inner side of the pressing point of each of the pressing rods 31 and is stationary. This is to prevent the opposite side of the pressing point of the ring 91 from floating.

  FIG. 4 is a side view showing the pressing rod 31, the stationary ring 91, and the roller 53. As shown in FIG. 4, the two spherical bearings 101 are provided between the pressing rod 31 and the stationary ring 91. The two spherical bearings 101 are configured to be capable of tiltingly supporting the two pressing rods 31 and function as tilting universal joints that can tilt in multiple directions. In the present embodiment, the load transmission unit includes two pressing rods 31 and two spherical bearings 101.

  FIG. 5 is an enlarged view of the spherical bearing 101 shown in FIG. Each spherical bearing 101 includes a bearing housing 102 formed integrally with the top of the stationary ring 91 and a cylindrical protrusion 103 that makes point contact with the bearing housing 102. The bearing housing 102 has a cylindrical recess 102a. The cylindrical protrusion 103 is formed integrally with the lower end of the pressing rod 31. The cylindrical protrusion 103 has a spherical lower end surface 103 a, and this spherical lower end surface 103 a is in point contact with the bottom surface of the recess 102 a of the bearing housing 102.

  The cylindrical protrusion 103 is gently fitted into the recess 102a, and the cylindrical protrusion 103 is inclined in all directions within the recess 102a in a state where the spherical lower end surface 103a is in point contact with the bottom surface of the recess 102a. Be able to. Therefore, the pressing rod 31 integrally connected to the cylindrical protrusion 103 can be inclined in multiple directions. The bearing housing 102 may be provided separately from the stationary ring 91. For example, the bearing housing 102 having the cylindrical recess 102 a may be fixed to the upper surface of the stationary ring 91.

  The two spherical bearings 101 as tilting universal joints that can be tilted in multiple directions can allow (absorb) the relative tilt between the local load applying device 30 and the retainer ring 20. Therefore, even when the local load applying device 30 and the retainer ring 20 are inclined, excessive frictional resistance does not occur between the linear guide 38 and the linear rod 39 (see FIG. 2), and the pressing rod 31 Excessive stress is not generated. Therefore, the local load applying device 30 can apply the intended local load to the retainer ring 20.

  FIG. 6 is a view showing another embodiment of the tiltable universal joint. In the embodiment shown in FIG. 6, the tiltable universal joint 110 is incorporated in the two pressing rods 31. More specifically, the pressing rod 31 is divided into an upper pressing rod 31A and a lower pressing rod 31B, the upper pressing rod 31A is connected to the bridge 32, and the lower pressing rod 31B is connected to the stationary ring 91. ing. The tilting universal joint 110 is provided between the upper pressing rod 31A and the lower pressing rod 31B, and connects the upper pressing rod 31A and the lower pressing rod 31B so as to be tiltable. In the present embodiment, the load transmission unit includes two pressing rods 31 and a tiltable universal joint 110.

  The tilting universal joint 110 includes an upper joint member 111, a lower joint member 112, and a pivot shaft 113 that rotatably connects the upper joint member 111 and the lower joint member 112 to each other. As shown in FIG. 7, the upper joint member 111 and the lower joint member 112 are configured to be able to tilt around a pivot shaft 113.

  FIG. 8 is a perspective view showing the local load applying device 30 and the polishing head 1 in which the tiltable universal joint 110 shown in FIG. 6 is incorporated. The axis of the pivot shaft 113 extends in the radial direction of the retainer ring 20, and the tiltable joint 110 can tilt only in the direction perpendicular to the axis of the pivot shaft 113. More specifically, the tiltable universal joint 110 can be tilted only in the tangential direction of the retainer ring 20 at a location where the two pressing rods 31 are connected to the stationary ring 91.

  The tilting universal joint 110 can allow (absorb) a relative inclination between the local load applying device 30 and the retainer ring 20. Therefore, even when the local load applying device 30 and the retainer ring 20 are inclined, excessive frictional resistance does not occur between the linear guide 38 and the linear rod 39 (see FIG. 2), and the pressing rod 31 Excessive stress is not generated. Therefore, the local load applying device 30 can apply the intended local load to the retainer ring 20.

  FIG. 9 is a diagram illustrating another embodiment of the load transmission unit. In this embodiment, the tilting universal joint 110 shown in FIG. 6 is combined with the tilting universal joint (spherical bearing) 101 shown in FIGS. In the present embodiment, the load transmitting portion is composed of two pressing rods 31, a tiltable universal joint 110, and a tiltable universal joint (spherical bearing) 101. The tilting universal joint 110 can be tilted only in the tangential direction of the retainer ring 20 at the place where the two pressing rods 31 are connected to the stationary ring 91, and the tilting universal joint 101 is freely movable in any direction over 360 degrees. Can lean on. Since the other structure of this embodiment is the same as the structure shown in FIG. 6, the overlapping description is abbreviate | omitted.

  FIG. 10 is a diagram showing still another embodiment of the load transmitting unit. In this embodiment, instead of the two pressing rods 31, one pressing block 120 is used as the pressing member. The tilting universal joint 110 is incorporated in the pressing block 120. More specifically, the pressing block 120 is divided into an upper pressing block 120A and a lower pressing block 120B, the upper pressing block 120A is connected to the bridge 32, and the lower pressing block 120B is connected to the stationary ring 91. ing. The tilting universal joint 110 is provided between the upper pressing block 120A and the lower pressing block 120B, and connects the upper pressing block 120A and the lower pressing block 120B so as to be tiltable. Since the other structure of this embodiment is the same as the structure shown in FIG. 6, the overlapping description is abbreviate | omitted.

  FIG. 11 is a diagram showing still another embodiment of the load transmission unit. In this embodiment, springs 125 as vibration absorbing members are respectively incorporated in the two pressing rods 31. Since the other structure of this embodiment is the same as the structure shown in FIG. 6, the overlapping description will be omitted.

  The spring 125 is incorporated in the lower pressing rod 31 </ b> B and is configured to absorb vertical vibrations of the retainer ring 20 caused by surface irregularities of the polishing pad 2. The spring 125 may be incorporated in the upper pressing rod 31A. According to the present embodiment, the tilting universal joint 110 allows (absorbs) the relative inclination between the local load applying device 30 and the retainer ring 20, and the spring 125 as a vibration absorbing member extends in the vertical direction of the retainer ring 20. Vibration can be absorbed. Therefore, the local load applying device 30 can apply the intended local load to the retainer ring 20.

  FIG. 12 is a diagram showing still another embodiment of the load transmitting unit. In this embodiment, the tiltable universal joint 110 shown in FIG. 6, the tiltable universal joint (spherical bearing) 101 shown in FIGS. 4 and 5, and the spring 125 shown in FIG. 11 are combined. Since the other structure of this embodiment is the same as the structure shown in FIG. 6, the overlapping description is abbreviate | omitted.

  In the embodiment shown in FIGS. 11 and 12, instead of the spring 125, rubber may be used as the vibration absorbing member.

  The embodiment described above is described for the purpose of enabling the person having ordinary knowledge in the technical field to which the present invention belongs to implement the present invention. Various modifications of the above embodiment can be naturally made by those skilled in the art, and the technical idea of the present invention can be applied to other embodiments. Accordingly, the present invention is not limited to the described embodiments, but is to be construed in the widest scope according to the technical idea defined by the claims.

1 Polishing head (substrate holding device)
DESCRIPTION OF SYMBOLS 2 Polishing pad 2a Polishing surface 3 Polishing table 5 Polishing liquid supply nozzle 10 Head main body 11 Polishing head shaft 15 Revolving shaft 20 Retainer ring 20a Ring member 20b Drive ring 30 Local load-applying device 31 Press rod 32 Bridges 33, 34, 35 Air cylinder (Load generator)
38 Linear guide 39 Guide rod 40 Unit base 43 Carrier 45 Elastic membrane (membrane)
46 Pressure chamber 47 Spherical bearing 48 Inner ring 49 Outer ring 53 Roller 60 Retainer ring pressing mechanism 61 Piston 62 Rolling diaphragm 63 Pressure chamber 75 Connecting member 76 Shaft 78 Spoke 80 Drive collar 91 Static ring 101 Spherical bearing (tilt universal joint)
102 Bearing housing 102a Depression 103 Cylindrical protrusion 110 Tilt universal joint 111 Upper joint member 112 Lower joint member 113 Pivot shaft 120 Press block 125 Spring

Claims (10)

A head body pressed against the polishing surface while rotating the substrate;
A retainer ring disposed so as to surround the substrate and pressing the polishing surface while rotating together with the head body;
A stationary ring disposed above the retainer ring;
A local load applying device that applies a local load to a part of the retainer ring through the stationary ring;
The local load applying device has a load transmission unit connected to the stationary ring,
The polishing apparatus according to claim 1, wherein the load transmitting unit includes a mechanism that allows a relative inclination between the local load applying device and the retainer ring.   The polishing apparatus according to claim 1, wherein the mechanism is a tilting universal joint.   The polishing apparatus according to claim 2, wherein the tiltable universal joint can be tilted only in a tangential direction of the retainer ring at a portion where the load transmitting portion is coupled to the stationary ring. The load transmitting portion is
A pressing member connected to the stationary ring;
The polishing apparatus according to claim 3, further comprising the tiltable joint fixed to the pressing member.   The polishing apparatus according to claim 2, wherein the tiltable universal joint can be tilted in multiple directions. The load transmitting portion is
Two pressing rods for transmitting the local load;
Two spherical bearings that respectively support the two pressing rods so as to be freely tiltable,
6. The polishing apparatus according to claim 5, wherein the tilting universal joint includes the two spherical bearings. The two spherical bearings are:
Two bearing housings;
The polishing apparatus according to claim 6, further comprising two protrusions that make point contact with the two bearing housings.   The polishing apparatus according to claim 2, wherein the load transmission unit further includes a vibration absorbing member.   The polishing apparatus according to claim 8, wherein the vibration absorbing member is a spring.   The polishing apparatus according to claim 8, wherein the vibration absorbing member is rubber.

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